Rotary pump



M y 3, 1927' s MEPSTEAD aoww PUMP Filed Oct 9, 1

fivmwra 65005:- 6 MEPSTEH ps9 M Patented May 3, 1927.

I onirsn STAT-ES PATENT-OFFICE.

GEORGE SIDNEY MEPSTEAD, or Lennon, ENGLAND.

ROTARY PUMP.

Application filed October 9, 1926, Serial No. 140,576, and in GreatBritain November 30, 1925.

This invention relates to rotary pumps of the type in which the pumpchamber comprises an annular compartment around which is adapted totravel a piston or radial blade member, the chamber having inlet andoutlet ports associated with it.

The object of the present invention is to incorporate in a pump of thistype certain features which provide a combination resulting in a highlyeflicient pump, these featin-es being obtained as the result ofexperiments with pumps of the type set forth, which hertofore have beenfar from. satisfactory.

.urcording to my invention a rotary pump of the type set forthcon'lprises in combina tion a cylindrical housing or casing havingformed in it an annular space within which is disposed a piston orradial blade member adapted to be rotated through said space so as totravel about the cylindrical inner wall of said space, said piston orradial blade 1nemher being shaped so that itwill. engage and move oncein every revolution in a substantially radial direction against theinfluence of spring means a movable wall member disposed across a pointin said annular space, said annular space having disposed in it eitherside of said wall member inlet and outlet ports.

In order that my invention may be clearly understood and readily carriedinto effect I have appended hereto a sheet of drawings illustrating anembodiment of same, and wherein 2- Fig. l is a part sectionalsideelevation view.

Fig. 2 is a. part sectional end view showinnone half of thcpump bodyremoved to show the interior of the pump.

Fig. 3 is an inner face view of one of the two elements constituting themovable wall member. and

Fig. 4; is an end radial piston.

Referring to the drawings, a housing is provided constituted by a pairof circular members 1 and 2 united in axial alignment in any suitablemanner and when so united providing an enclosed annular chamber 3 aroundwhich is adapted to travel a radial blade or piston 41: secured to theperiphery of a disc 5 carried by a shaft 6 supported for axial rotationin the housing. The shaft 6 can be rotated by any suitable means and asuitable packing gland 7 is preferably sectional view of the moresprings 13 provided to reduce leakage. In order to enable a compressionor expansion action to be produced by the movement of the blade l, amovable-member 8 bridges across a part of the annular chamber 3so-as tointerrupt its continuity and to provide two end walls similar to bendinga straight axis cylinder so as to bring its two ends together. Thismember 8 abuts into the inner periphery of the chamber 3, and has itsedge engaging such inner periphery curved so that the cam shaped radialblade 4:.Will rid-e evenly over 9 the intluenccof whichis overcome bythe pressure of the piston l against the member 8 so as to raise itmomentarily to allow the piston to commence another stroke. In Fig.

2 the piston 4 is rotating anti-clockwise and inlet and outlet ports 10and 11 respectively are provided adjacent the member 8. It will be seenthat the blade 4 effects a simultaneous expansion and compressionstroke.

Referring more in detail to the various elements above described I willnow introduce the more important features of such elements.

I have found in pumps of the type to which this inventionrelates that agreat loss in efiiciency arises out of leakage past the edges of thepiston 4L and to obviate this the piston 4i is grooved or channelled thefull length of its free ednje to receive a strip 12 which at all timesduring the working of.

thepump is maintained pressed by one or against the outer wall of thechamber IThis strip 12 is preferably dovetailed in cross section. itsinner face heins; the wider. the channel accommodating it being slightlylarger but correspondingly shaped to receive the strip 12, whereby thestrip 12 is safely held in. position.

The ends of the piston 4 are recessed in a radial direction to receiveend plates 14: (see more particularly Fig. 4) each of which is pressedout against the side walls of the annular chamber 3 to prevent leakagepast the ends of the piston. The end plates 14 are reduced in width attheir outer ends as indicated at let 111mg. 2 to engage in recessed orcut-away portions at the ends of the strip 12. I i

To prevent to a large extent any leakage past the wall member'S. theinner edge of thesaid wallmember is adapted to seat into sha ittbearings, the

eating li'verysides of-the piston a recess 8 disposed across the innerconcentric wall of the chamber 3 and at the same time engaging theperiphery of the disc 5. The radial edges of the wall 8 also slide inradial grooves 8 disposed across the annular chamber 3 and continuouswith the radial ends of the compartment 15 within which the wall 8moves. By this means a nice sliding; tit of the wall member 8 isobtained.

The springs 9 of the plung'ers 9 are acconnnodated in radial cylindricalrecesses 16 in the body of the pump, the said springs being disposedbetween flanges 9 on the plungers 9 and in upper ends of hollow caps 17threaded into the recesses 16. By this means the springs 9 and plungers9 can be removed when desired without disassembling the pump.

To ensure that the wall member 8 always has a tightfit in the chamber 15so as to minimize leakage past the sides of the wall member as much aspossible the all member is preferably composed of two plides (z and 7)(see Fig. which have interposed between them a sprii'ig which may be anarcuate sprinp 18 secured to one of the plates and accommodated inregistering horizontal channels 19 in "the plates a and Z). One plate(Z) in the drawings) overlaps the other plate at the upper end asindicated at c. the shorter plate (a) being shaped at its upper end asindicated at (Z to lit in a corresponding recess 0 across the plate Z).The lower edge of the plate 7) is rounded to ensure that the slopingside of the piston 6: will'eng'age and raise the wall 8, the lower edgeof this plate 7) overlapping the plate a. By this means the wall member8 e'liiciently seals the space within which it works.

It desired the planners 9 may be en graged in a rectilinear ill sectionmember the same width as the chamber 15 and resting upon the upper edgeof the wall member 8 thereby sealing the space above the member 8against the leakage of fluid into such space.

To etlectively lubricate the shaft 6 an oil or grease chamber 20 isdisposed in the body of the 'pump so as to communicate with the shaft ifdesired having helical or other peripheral grooves therein forlubricating purposes. A suitable lubri cap 'is provided in the body forcharging thechamber '20. A similar chamher 20 is preferably providedwith the opposite end of the pump body adjacent the gland of the shaft6.

The thickness of the plate .5 is very narrow compared with the width ofthe piston l so as to reduce :as far as poss'ble the gap 5" in the innerconcentric wall of the annular chamber 3, thereby obviating as far aspossible leakageb'etween the suction and de- 4-. To strengthen the plate0 It is preferably formed with a concentric boss 21 upon both sides. The

plate 5 is a ground lit in the body and with a high eliicioncy pump theannular sides of the plate 5 can be titted with expanding annular rings.

The direction oi rotation ol the piston 4; is indicated by the arrow inFig. 2, and consequently the space in the annular chamber between theoutlet port 1 l and the wall member 8 in the absence of any provision tothe contrary would be an idle space impairing the elliciency of thepump. To ob viate this loss in eiiiciency. I provide a passage 22communicating; with the outlet 11 and the face or the wall member 8which receives the pressure of the fluid being driven out by the movingpiston 4. By this means practically all of the fluid drawn into thechamber 3 through the inlet port 10 during one revolution of the piston.will during the next revolution of the piston be swept out of the outletport 11.

Suitable lubricating passages 23 are provided in the cap 24: foradmitting lubricating oil to the chambers 16 and 15, a suitablelubricator being threaded into a recess 24'- common to all of thepassages 23.

Ill desired instead ot a single wall incinher 8 a pair of symmetricallyarranged wall inen'ihers may be l'n'ovided, one tor each port 10 and1.1, the distance between these two wall members being sutticient toensure that one is dispo across the chamber 3 before the other is movedby the piston 41-. This insures a thorough check on the closing of thespace between the valves 10 and 11.

1. A rotary pump comprising a cylindrical casing, concentric internallyprojecting bosses on the ends of the casing forming; a broad andcompzu'atively shallow annular space between the periphery of the bossesand the periphery of the casing a rotatable disc fitting between thebosses, a cam shaped piston mounted on. the disc and titting thc annularspace, a slidable wall member engaging in grooves in the casing,resilient means to normally urge the wall member toward the periphery ofthe rotary disc, inlet ports in the casing on one side of the movablewal'l member and outlet ports in the casing on the other side of thesaid movable wall member.

2. A rotary pump (.omprising-a cylindrical casing, concentric internallyprojecting'bosses on the ends ct the casing forming a lnroad andcomparatively shallow annular space between the periphery oi. the bossesand the periphery ot the casing. a rotatable disc littinp 'between thehos a-cam shaped piston mounted on the disc and fitting; the annularspace. packing strips located in the faces of the piston and press doutwzn'dlv by resilient means to engage the walls or the annular space,a sli'dable wall memberengaging in grooves in the casing, resilientmeans to normally urge the wall member towardthe periphery of the rotarydisc, inlet ports in the casing on one side of the movable wall memberand outlet ports in the casing on the other side of the said movablewall member,

3. A rotary pump comprising a cylindrical casing, concentric internallyprojecting bosses on the ends of the casing forming a broad andcomparatively shallow annular space between the periphery of the bossesand the periphery of the casing, a rotatable disc fitting between thebosses, a cam shaped piston mounted on the disc and fitting the annularspace, packing strips located in the faces of the piston and pressedoutwardly by resilient means to engage the walls of. the annular space,a slidable wall member engaging in grooves in the casing and formed intwo pieces, interlocking ridges and grooves on the two parts, springmeans be tween the two parts to press them apart and against thechannels in which they may slide, resilient means to normally urge thewall member toward the periphery of the rotary disc, inlet ports in thecasing on one side of the movable wall member and outlet ports in thecasing on the other side of the said movable wall member.

4. A rotary pump comprising a cylindrical casing, concentric internallyprojecting bosses on the ends of the casing forming a broad andcomparatively shallow annular space between the periphery of the bossesand the periphery of the casing, a rotatable disc fitting between thebosses, a cam shaped piston mounted on the disc and fitting the annularspace, packing strips located in the faces of the piston and pressedoutwardly by resilient means to engage the walls of the annular space, aslidable wall member engaging in grooves in the casing and formed in twopieces, interlocking ridges and grooves on the two parts, spring meansbetween the two parts to press them apart and against the channels inwhich they may slide, overlapping upper and lower lips on one part, arounded lower edge on the leading side of the wall member, resilientmeans to normally urge the wall member toward the periphery of therotary disc, inlet ports in the casing on one side of the movable wallmember and outlet ports in the casing on the other side of the saidmovable wall member.

5. A rotary pump comprising a cylindrical casing, concentric internallyprojecting bosses on the ends of the casing forming a broad andcomparatively shallow annular space between the periphery of the bossesand the periphery of the casing, a rotatable disc fitting between thebosses, a cam shaped piston mounted on the disc and fitting the annularspace, packing strips located in the cal casin faces of the piston andpressed outwardly by resilient means to engage the walls of the annularspace, a slidable wall member engaging in grooves in the casing, andformed in two pieces, interlocking ridges and grooves on the two parts,spring means between the two parts to press them apart and against thechannels in which they they slide, overlapping upper and lower lips onone part, a rounded lower edge on the leading side of the wall member,at least one spring pressed plunger to normally urge the wall membertoward the periphery of the rotary disc, inlet ports in the casing onone side of the movable wall member and outlet ports in the casing onthe other side of the said movable wall member.

6. A rotary pump comprising a cylindriical casing, concentric internallyprojecting bosses on the ends of the casing forming a broad andcomparatively shallow annular space between the periphery of the bossesand the periphery of the casing, a rotatable disc fitting between thebosses, a cam shaped piston mounted on the disc and fitting the annularspace, packing strips located in the faces of the piston and pressedoutwardly by resilient means to engage the walls of the annular space, aslidable wall member engaging in grooves in the casing and formed in twopieces, interlocking ridges and grooves on the two parts, spring meansbetween the two parts to press them apart and against the channels inwhich they may slide..overlapping upper and lower lips on one part, arounded lower edge on the leading side of the wall member, at least onespring pressed plunger to normally urge the wall member toward theperiphery of the rotary disc, a removable cap to enclose the upper endof each spring pressed plunger, inlet ports in the casing on one side ofthe movable wall member and outlet ports in the casing on the other sideof the said movable wall member.

7. A rotary pump comprising a cylindriconcentric internally projectingbosses on the ends of the casing forming a broad and comparativelyshallow annular space between the periphery of the bosses and theperiphery of the casing, a rotatable disc fitting between the bosses, acam shaped piston mounted on the disc and fitting the annular space,packing strips located in the faces of the piston and pressed outwardlyby resilient means to engage the walls of the annular space, a slidablewall member engaging in grooves in the casing, and formed in. twopieces, interlocking ridges and grooves on the two parts, spring meansbetween the two parts to press them apart spring pressed plunger tonormally urge the wall member toward the periphery of the rotary disc aremovable cap to enclose the upper end of each spring pressed plunger,inlet ports in the *asing; on one side of the movable wall member,outlet ports in the casing on the other side ot the said movable wallmember, and an auxiliary outlet port extending from near the movablewall into the main outlet ports.

8. A rotary pump comprising a cylindrical casing termed in two partssplit transversely to its axis concentric bosses on each part forming awide but comparatively shallow annular space between their periphery andthe peripheryot the casing, a shaft mounted in bearings in the bosses adisc on the shaft and fitting between the ends of the bosses, a camshaped piston projecting from the periphery of the disc and fittingagainst the walls of the annular space, spring pressed packing strips inthe piston tacos, a slidable wall member formed of two pieces tittedface to face, interlocking ridges and recesses on the two pieces,overlapping upper and lower edges to one piece, a rounded lower edge tothe piece against which the cam-shaped piston engages, grooves in thewalls of the casing and the periphery of the bosses in which the movablewall member engages, a recess in the easing into which the wall membermay slide to permit the piston to pass, spring means between the piecesof the wall member to force them apart, plnng'ers engaging against theouter end of the wall member, springs acting on the plungers so as tocause them to urge the wall member toward the axis of the pump,removable caps enclosing the outer ends of the said springs, inlet portson the casing on one side of the wall member, outlet ports in the casingon the other side thereof, an auxiliary outlet port extending; from nearthe wall member into the main outlet ports, and means for feedinglubricant to the wall member and the interior of the pump and to thepump shaft.

GEORGE SIDNEY MEPSTEAD.

